390 



STATE BOARD OF AGRICULTURE. 



agreement. Various smaller inland blows occur throughout the southern 

 peninsula, usually only a few acres in extent but nevertheless serious 

 from the owner's standpoint. These smaller blows are readily handled 

 by the owners. Close adherence to the principles of the shelter belt 

 cover system as hereafter outlined will usuallj^ insure complete control 

 of these smaller inland blows. No difliculty is experienced in establish- 

 ing a permanent stand of young forest trees at once by planting. After 

 one year some trees will be blown out while others will be covered up. 

 Often it becomes necessary to use dead cover to protect the planting for 

 the first three or four years. Less than 20% of the trees planted are 

 usually lost in this way. 



TOTAL SAND AREA. 



Bordering on the Great Lakes, Michigan has at least 534,000 acres 

 of dune formed land. This is stretched out in belts of sand agjjregatins: 

 a total length of four hundred miles. 



•&&' 



Fig. 3. The point of high water, or the point where the wind catches the sand. The 

 bank of sand is here well planted to beach grass, and must be followed by tree planti^. A 

 disturbance or break in this grass cover, made by a foot trail or wagon wheels, is sufficient 

 to make a wind path for the sand which may develop rapidly into a traveling dune. 



THEORY OF NATURAL FORMATION OF THE ORIGINAL DUNES. 



It is probable that no change has occurred during the process of time 

 in the general formation of sand piles called dunes. The ceaseless action 

 of water, wind and temperature breaks down rocks into increasingly 

 smaller particles and rounds off the angles of the grains. Constantly 

 these grains are cast upon the shore by the waves. The sun's heat soon 

 dries the grains and the wind rolls them higher over the smooth sand 

 surface, finally depositing them with masses of others in drifts and 

 banks on the leeward slope of the newly formed drifts. During this time 

 of wind and water formation of the dune, the vegetative forces are also 



